Senate Majority Leader Mitch McConnell on Wednesday told The New York Times that he thinks the “blue slip” practice should be scrapped for circuit court nominations, a move that would eliminate Democrats’ only leverage against President Donald Trump’s picks to the nation’s second-highest courts.

“My personal view is that the blue slip, with regard to circuit court appointments, ought to simply be a notification of how you’re going to vote, not the opportunity to blackball,” McConnell told The Times, adding that he still favours keeping the practice in place in its current form for district court judges.

Responding to McConnell, Senate Majority Leader Chuck Schumer told The Times that “getting rid fo the blue slip would be a mistake.”

“Preserving some of the minority’s power in the Senate has broad support because every one of us knows we’re probably going to be in some of each,” he said.

Last Tuesday, Democratic Sen. Al Franken of Minnesota refused to sign off on Trump’s nomination of Minnesota Supreme Court Judge David Stras for a vacancy on the 8th US Circuit Court of Appeals. Franken said he could not support Stras, nominated by Trump in March, and would not be returning a blue slip to the Senate Judiciary Committee.

On Thursday, Sens. Jeff Merkley and Ron Wyden of Oregon announced they would block Ryan Bounds, an assistant US attorney in Oregon, from a seat on the 9th US Circuit Court of Appeals. The duo said in a letter to the White House that they would not be providing blue slips for Bounds because he had not been approved by a bipartisan judicial selection committee in their state.

The “blue slip” process is Senate tradition in which senators are able to give or withhold their blessing for a judicial nomination from their state. It’s not an entirely uncommon practice to block the nominees, as several of President Barack Obama’s judicial nominees met the same fate.

While the denial of a blue slip does not legally restrict a judge from being approved, Glenn Sugameli, an attorney who is an expert on judicial nominations, told Business Insider in an email last week that “no circuit court nominees have been confirmed over objection of one (or two) home state senators — including under Obama.”

Roughly 80% of Trump’s nearly 50 nominations to such courts have come from states that are represented by two Republican senators. Just five nominees hail from states with two Democratic senators. The roughly 80% of nominees coming from states with two senators of his party is a much higher percentage than Obama’s nominations from such states the same point in his presidency back in 2009.

The intent of the blue-slip process is to have a more bipartisan consensus on judges who will serve in or represent a senator’s home state when the president is of the opposition party, encouraging communication between the White House and home-state senators before a nomination.